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The “USRA look” Slightly flared smokestack Domed smokebox door Overhung bell Headlight slightly below center Rounded sandbox and steam dome Gambreled cab roof “Classic” tender with raised fuel bunker Running board steps Spoked pilot Alligator crosshead Single cross-compound air compressor on left side Built-up trailing truck, Hodges type shown Andrews tender trucks Louisville & Nashville class J-3 2-8-2 no. 1512, one of eighteen original light Mikados built for the “Old Reliable” road by Lima in 1919, is still a fine example of the USRA look at Atlanta in 1939. Richard E. Prince photo Locomotive historians recognize a family resemblance between the USRA designs. The locomotives were often modified by the owning railroads, sometimes considerably, but usually some traces of USRA ancestry remained. These were the characteristics of the USRA look: • Overhung bell at top front of smokebox (except on switchers, where it was atop the boiler). • Headlight just below center line of smokebox (except on switchers and Mallets), on bracket with rectangular number plate. • Domed, well-proportioned smokebox door with multiple bolts and dogs (except on Mallets). • Spoked “boiler tube” pilot (except foot boards on switchers and the rear of switcher tenders). A common rule of thumb was that a steam locomotive’s fastest safe speed in miles per hour equaled its driver diameter in inches plus about 10 percent. Of the USRA engines, that was probably truest for the Pacifics. The light Pacific’s 73" drivers did allow it, with favorable loads and grades, to reach about 80 mph. The 79" heavy Pacific could exceed that speed with trains of moderate size. In 1920s practice most railroads restricted engines with 63" wheels to speeds of 50 to 55 mph, if not less, and engines with 57" wheels to about 35 mph. When run faster, the heavy side rods of lower-wheeled engines generated pounding forces that couldn’t be controlled by counterbalancing. They not • Slightly flared smokestack. • Neat, simple sandbox and steam dome, with sandbox on first boiler course (two sandboxes each on 2-10-2s, Mallets, and switchers). • Single cross-compound air compressor on left side of boiler (except on Mallets). • Steps up to running boards over cylinders (except switchers and the initial light Mikado). • Gambreled (barn-like) cab roof. • Fabricated (not cast) outside-bearing trailer truck (except switchers and 2-8-8-2). • Well-proportioned tender with raised coal bunker. • Andrews tender trucks (except some passenger engines). – Andy Sperandeo only became uncomfortably rough-riding at higher speeds, they damaged both the track and their own bolted main frames. Railroads found speed restrictions more acceptable than costly increased maintenance. Later locomotives included features such as cast engine beds with integral cylinders, roller bearings, disk drivers, and lightweight side rods. In many instances these more modern engines could smoothly reach and maintain speeds greater than the rule-of-thumb factor of their wheel diameters. Notable types More light 2-8-2s were built than any other USRA locomotive, not surprisingly 50 Model Railroader • www.ModelRailroader.com given the popularity of the Mikado for all kinds of freight service. Also, large numbers of light 2-8-2 copies were built after USRA control ended. Despite its wide acceptance, however, by the mid1920s the 2-8-2 was being eclipsed by newer freight engines with four-wheel trailing trucks. These supported larger fireboxes to generate greater horsepower. Now on ModelRailroader.com See listings of USRA locomotive allocations by type and railroad, and of mass-produced USRA locomotive models from N to G scales, online at www.ModelRailroader.com.